1. Field of the Invention
This invention relates to novel metal rolling oil compositions and more particularly, to metal rolling oil compositions comprising lubricant oil components and water-soluble cationic or amphoteric polymer compounds.
2. Description of the Prior Art
Generally and hitherto employed metal rolling oils comprise lubricant oil components such as fats and oils, mineral oils or aliphatic esters admixed with auxiliary agents such as oily improvers, extreme pressure additives, rust inhibitors, antioxidants and the like. These components are formed into an O/W-type emulsion using emulsifiers and supplied to the rolling process generally at a concentration of 1 to 20%. The recent, rapid advancement in rolling facilities and techniques permits high speed rolling and mass production and hence the demand on rolling oils with respect to their circulating lubrication stability, workability, waste water treatability and the like becomes severer. Accordingly, the development of such rolling oils as to meet the above demand is strongly desired. In this connection, however, conventional rolling oils using emulsifiers have a number of difficulties and are not satisfactory. That is, in knwon rolling oils using emulsifiers, the rolling lubrication is controlled by changing the type and amount of emulsifiers and controlling the amount of oil (plating-out amount) deposited on the surface of materials to be rolled. However, in these rolling oils using emulsifiers, the plating-out amount and the liquid circulation stability tend to be contrary to each other, i.e. an increasing stability of emulsion results in insufficient lubricativeness because of the reduction of the plating-out amount on rolling materials. An increase of the plating-out amount causes the emulsion unstable with the attendant drawbacks such as various troubles in application by circulation.
The present inventors have made studies so as to overcome the drawbacks of the known emulsified rolling oils and succeeded in overcoming the drawbacks and applied for a patent (Japanese Laid-open No. 55-147593) in which lubricating components containing fats or waxes are so dispersed using a specific type of hydrophilic dispersant that they are stably suspended and dispersed in water in the form of oil particles.
We have made further studies and found that although the rolling oils of such preceding application are much improved over the known emulsified rolling oils, there is still left the problem that the particles are more finely divided under conditions of a shearing force higher than a certain level (10,000 r.p.m. of a homogenizer mixer) s will be shown in examples 1-3 appearing hereinafter, so that it is difficult to form a thick, tight lubricating film on a metal material to be rolled.